Automatic test equipment (ATE) (referred to generally as a “tester”) is used to test semi-conductor devices during their manufacture. Functional testing is typically performed by configuring a tester to apply electrical signals to numerous points on the device under test (DUT) while measuring the output response of the DUT at certain points.
In some scenarios, testers are used to test DUTs to identify defects at least once during the process of manufacturing the DUTs. The results of testing can be used to determine whether a DUT behaves as designed. If the device behaves as designed, the device may be packaged and shipped to a customer. If tests indicate that the device does not behave as designed, the device is often diverted to further manufacturing steps, such as repair or disposal.
To generate and measure test signals required to test a semiconductor device, a tester includes circuitry, sometimes called pin electronics, that can be controlled to generate and/or measure a test signal. Testers can be programmed to generate and measure test signals at each of multiple test points on a device under test in each of multiple cycles of tester operation by specifying an operation of the pin electronics. For each cycle of tester operation, the test program may specify an action for each pin electronics circuit coupled to a test point. The programming may define what that action is, such as driving a HI or LO signal or measuring whether the DUT is outputting a HI or LO signal. The programming may also specify the timing of that action relative to the start of the tester cycle. In this way, a test program may be built up to apply a wide range of stimulus signals to a DUT and to measure whether the DUT produces an expected response. However, specifying operations and timing for the many test points required to fully test a DUT can be time consuming.
Current semiconductor devices are quickly superseded by the next generation of semiconductor devices. To justify the large expense of designing a complex semiconductor device and establishing a manufacturing facility, semiconductor manufacturers seek to manufacture and sell as many devices as possible before the design becomes obsolete. That goal translates into a desire to put a device into production as soon as possible and to manufacture each device in as little time as possible.